Apparatus for forming sand piles

ABSTRACT

An apparatus for forming compacted sand piles the apparatus is provided with a sleeve fitted slidably into the lower portion of a casing pipe and a removable neck portion which moves in the an associated relationship with said sleeve at said casing pipe at the upper position spaced appropriately from the lower end of said casing pipe thereby to be able to form the compacted sand piles.

United States Patent 1 1 Shono M lMarch 13, 1973 APPARATUS FOR FORMING SAND [56] References Cited PHES UNITED STATES PATENTS [76] Inventor: Masaru Shono, l8, 5-chome, Tezu- 1 2,830,443 4/1958 Burrell ..6l/53.64 Osaka 3,303,656 2/1967 Landau aPam 3,498,066 3 1970 Nishimura etal. ..61 63 [22] Filed: Aug. 4, 1971 Primary Examiner-Jacob Shapiro [21] APP/1,1; i 168,830 Attorney-Eric H. Waters et al.

[30] Foreign Application Priority Data ABSTRACT May 25,1971 Japan ..46 35666 Ah apparatus for forming compacted Sand Piles the apparatus is provided with a sleeve fitted slidably into 52 U.S. Cl. ..6l/11, 6l/53.64, 61 63 the lower Portion of a casing P and a removable 51 1111.01 ..E02d 3/08, E02d 5/34 neck portion which moves in the an associated rela- [58] Field of Search ..61/11, '13,63,53.64,53.66, tiohship with Said Sleeve at Said Casing P p at the upper position spaced appropriately from the lower end of said casing pipe thereby to be able to form the compacted sand piles.

8 Claims, 19 Drawing Figures PATENTEUMAR 1 3197s SHEET 1!]? 4 PATEP'HEUHAR I 31973 SHEET 2 OF 4 FIG. 4A FIG.4B

PATENTEURARI 3 ms SHEET H1 4 APPARATUS FOR FORMING SAND PILES The present invention relates to an apparatus for forming compacted piles of sand or like granular materials in soft ground for the purpose of stabilizing ground surface thereby causing the water content in the soft ground to be discharged out of the ground surface by way of a drain formed by the sand piles has been known as a so-called Sand Drain Method. This known method has been popularly utilized in order to stabilize soft ground, but there are drawbacks such as for example it takes a rather long time to discharge the water content of the soft ground and also it requires a great deal of labor to impose a load on the ground surface and to remove the imposed load.

As an improved method relative to the afore-mentioned Sand Drain Method, another method as described below has also been known. This additionally known method is carried out by forming a large number of compacted sand piles in soft ground, each pile having a diametei' larger than that of the casing pipe, applying a'pressure to the soft ground around the sand piles by said compacted sand piles, and then discharging the water content of the soft ground out of the ground thereby stabilizing the soft ground to a compacted and reinforced state. In this last-mentioned method of forming compacted sand piles, at first, a casing pipe is driven into the soil down to a predetermined depth, Thereafter the driven casing pipe is pulled out slightly upward. Then the casing pipe is filled with sand and the sand is allowed to flow down into the cavity formed within the soil at the lower portion of the casing pipe by the pulling-out process, The casing pipe is again driven into the, soil in order to compact the sand which has flowed down into said cavity. Then, the casing pipe is pulled slightly upward again, and the same process is repeated until compacted short sand piles are formed consecutively up to the ground surface.

As the apparatus for forming sand piles to be employed in forming the compacted sand piles mentioned above, there have been in general employed an apparatus in which a hopper is provided at the upper portion, a drive machine provided at the top portion of the casing pipe, and an opening and closing cover fixed to the lower end of said casing pipe apparatus in which in place of the afore-mentioned opening and closing cover, a neck portion may be provided within the casing pipe in the neighborhood of the lower end thereof. The neck portion serves to close the casing pipe by utilizing the arch action of sand at the time of driving the casing pipe. Defects in these conventional apparatuses make it difficult for the sand fed into the easing pipe to be discharged smoothly on account of obstructions of the opening and closing cover mechanism or the neck portion. For example, in the case of forming the compacted sand piles by employing the conventional sand pile forming apparatuses, the sand piles are often produced in undesirable form; that is, often the sand piles to be formed are slender in their middle portion and are disrupted halfway. Consequently, there are many cases in which even though a sand quantity sufficient for that required for the sand piles to be compacted is supplied, continuity of the compactedly formed sand piles cannot be obtained.

The above-mentioned compacted sand piles in the undesirable form are likely to be produced particularly at the time when the casing pipe commences to cause a pulling action again, because in many cases the opening and closing cover is not moved rapidly and accurately from the closed state to the opened state at the time of the re-pulling out operation of the casing pipe. Even though the above-mentioned operation is carried out rapidly, there are many cases wherein discharge of the sand within the casing pipe does not follow closely to the re-pulling out operation of the casing pipe, Also in the casing pipe having a neck portion, the pipe is choked up with sand at the neck portion whereby discharge of the sand within the casing pipe does not follow closely to the re-pulling out operation. As mentioned above, in the case wherein discharge of the sand fed into the casing pipe is not correct at the time of the re-pulling out operation, the sand piles become extremely slender and also may be disrupted by the pressure of the surrounding soil or by the pressure of excess pore water.

It is an object of the present invention provide an improved sand pile forming apparatus capable of forming a compacted sand pile which has a preferred shape and continuity, with no disruption nor any slender portion in the middle thereof.

For attaining the above-mentioned object and other objects of the invention, the apparatus for forming sand piles according to the present invention is provided with a sleeve pipe fitted slidably into the lower portion ofa casing pipe and with a movable neck portion which moves in association with the said sleeve pipe at a certain upper position within the pipe spaced from the lower end of the said casing pipe.

The embodiments according to the present invention will be more clearly understood by reference to the following detailed description taken with the accompanying drawings in which:

FIG. 1 is a side view of a first embodiment of the invention in which a casing pipe and a hopper are shown in a longitudinal section;

FIGS. 2(a)(c) are detailed views of essential parts of the apparatus shown in FIG. 1, FIG. 2(a) being transverse sectional view taken along line A A of FIG. 2(b); FIG. 2(b) is a longitudinal sectional view of a casing pipe in the driving-in state in the neighborhood of the lower end; and FIG. 2(0) is a longitudinal sectional view in the neighborhood of the lower end of the casing pipe in the pulling-out state;

FIG. 3 is-a side view of a second embodiment of the invention, in which a casing pipe and a hopper are shown in a longitudinal section, and in which a driving source of a forcibly and vertically reciprocating mechanism is shown in a block diagram;

FIGS. 4(a)(b) are detailed views of essential parts of the apparatus shown in FIG. 3, in which FIG. 4(a) is a longitudinal sectional view in the neighborhood of the lower end of a casing pipe in the driving-in state; and FIG. 4(b) is a longitudinal sectional view in the neighborhood of the lower end of a casing pipe in the pulling-out state;

FIGS. 5('I)-(IV) are illustrative views which show successively the stages in forming compacted sand piles in the soft ground by using apparatus shown in FIGS. 1 and 2;

FIG. 6 is a graphic representation showing the operation of a casing pipe which corresponds to that in FIG.

FIGS. 7 through 9 show respectively modifications of the first embodiment shown in FIG. 2 (FIGS. 8 and 9(0) showing respectively the shape of a casing pipe in the driving-in state; and FIG. 9(b) showing the shape of a casing pipe in the pulling-out state; and

FIGS. and 11 show respectively modifications of the second embodiment shown in FIG. 4.

The first embodiment of the present invention will be explained with reference to the FIGS. 1 and 2 hereinafter.

In these figures, there is shown a casing pipe 1, and upper portion of the casing pipe 1 is provided with a hopper 2 and the top portion of said casing pipe is provided with a pile driver 3. As the said pile driver 3, a vibratory pile driver is generally employed. Next, a sleeve 4 is slidably fitted at the lower end portion of the casing pipe 1. Within the casing pipe at the upper position spaced appropriately from the lower end of said casing pipe 1, several plates or upper segments 5 are radially arranged, and each base side of an upper segments is hinged to the inner wall of said casing pipe. The lower segment 6 are respectively arranged in correspondence with said upper segments 5 below the latter, each upper side of said lower segments being hinged to a bottom side of an upper segment and also each lower side of a lower segment being hinged to the upper periphery of said sleeve 4. The hinged segments form a collapsible structure.

As shown in FIG. 2(b), in the state in which said sleeve 4 is slidably moved upward and the total length of said sleeve 4 substantially overlaps the lower end of said casing pipe 1 in nesting relation therewith, said upper segments 5 and said lower segments 6 come to a V-shape turned sideways by which a controllable neck portion 7 is formed. In such case, for preventing said sleeve 4 from moving further upward, a stopper 8 is provided at the lower periphery of said sleeve 4. Next, in the state in which said sleeve 4 moves slidably downward and its lower half portion hangs and projects downwardly from the lower end of said casing pipe, as shown in FIG. 2(b), the upper segments 5 and the lower segments 6 which constitute a neck portion 7 come to a substantially vertical attitude along the inner wall of the casing pipe 1, that is, the removable neck portion 7 disappears and accordingly the lower end of the casing pipe 1 is fully opened.

In the embodiment shown in FIGS. 1 and 2, there is shown a casing pipe made of steel pipe of square section but, as occasion demands, steel pipe of circular or polygonal section also can be employed. It is also possible to employ the steel pipe of circular section in the main body of the casing pipe and employ the steel pipe of square section only in the lower portion thereof. Further, in the embodiment shown in FIGS. 1 and 2, the sleeve 4 is fitted in the inner side of the casing pipe I, but as shown in FIG. 7, it is also possible to fit said sleeve in the outer side of the casing pipe 1. In this case, a slit 9 is provided on the pipe wall at the lower end of the casing pipe 1, said slit serving for passing through a portion connecting the upper portion of the sleeve 4 and the lower segments 6. The upper portion of the sleeve 4 is connected to a case pipe 10 for covering said slit 9.

Referring to FIGS. 5 and 6, the process of forming a compacted sand pile having a diameter larger than that of the casing pipe 1 in the soft ground by employing the apparatus according to the first embodiment of the present invention will next be explained.

First, as shown in FIG. 5(l), the casing pipe 1 is driven into the soft ground to a required depth by actuating the vibratory pile driver 2. In this case, the sleeve 4 which is in the lower end of the casing pipe 1 is moved upward due to the soil resistance and the upper segments 5 and the lower segments 6 come to the V- shape turned sideways thereby to form the neck portion 7 which is automatically movable. Accordingly, the lower end of the casing pipe 1 is shut by the arch action of the soil and the casing pipe 1 is driven into the ground in the hollow state.

In the case of driving-in operation of the casing pipe 1, it is also possible to provide sand 11 at the lower end of the casing pipe 1 as occasion demands. Then, an appropriate quantity of sand 12 is supplied from the hopper 2 into the casing pipe 1, and, as shown in FIG. 5(II), the casing pipe 1 is pulled out and upwardly by an appropriate amount. In this operation, the sleeve 4 is moved upwardly but due to its weight, friction against the surrounding soil, and the pushing-down force which is received by the upper segments 5 on account of the weight of sand supplied into the pipe, the upper segments 5 and the lower segments 6 come to a substantially vertical attitude and the controllable neck portion 7 disappears. As a result, the lower end of the casing pipe 1 is fully opened, and the sand 12 supplied into the pipe flows down into the cavity formed in the ground under the lower end of the casing pipe 1 after the pulling-out of the casing pipe. Next, as shown in FIG. 5(III), the casing pipe 1 is driven downwardly, and consequently the sleeve 4 comes to the state as shown in FIG. 5(1) resulting in the neck portion 7 being automatically formed again and the lower end of the casing pipe 1 being shut due to the arch action of sand whereby the sand column 12' which has flowed down into the cavity formed in the ground under the lower end of the casing pipe 1 is compacted whereby its diameter becomes larger than that of the casing pipe 1. By repeating such pulling-out and redriving-in operations of the casing pipe 1 in turn, as shown in FIG. 6, a compacted sand pile 13 having a diameter larger than that of the casing pipe 1 is formed starting from the desired depth to the ground surface, as shown in FIG. 5(IV).

In forming the compacted sand piles according to the process as mentioned above, when the casing pipe 1 is pulled out, the neck portion 7 disappears and the lower end of the casing pipe 1 is fully opened such a degree that it shows a nearly full sectional shape. Accordingly, the sand 12 fed into the casing pipe favorably blows down to the lower portion of the pipe and at the same time the sleeve 4 inserted into the lower end of the casing pipe 1 hangs and projects downwardly from the lower end of said casing pipe. Therefore, one advantage of the present invention is that said sleeve 4 can prevent the pressure of the surrounding soil and the back-flowing of said surrounding soil into the casing pipe. Another advantage is that the hanging and projecting of said sleeve 4 from the lower end of the casing pipe can cover the timelag between the flowing down of the sand 12 and the upward movement of the lower end of the casing pipe 1 at the time of the pulling-out operation of the casing pipe. Accordingly, the present invention can prevent effectively the forming of unfavorable shapes of sand pile and the causing of disruptions or extremely narrow portions, as often seen in the settlement of compacted piles by use of conventional apparatus.

As a result of experiments using the apparatus according to the present invention, it has been found that compacted sand piles having extremely favorable shapes and securing continuity can be obtained, in

comparison with sand piles formed by the use of conventional sand pile forming apparatus.

Next, the second embodiment inthe present invention will be explained with reference to FIGS. 3 and4 hereinafter.

This apparatus is so constructed that a forcibly reciprocating mechanism is additionally provided inside the casing pipe 1 and by the reciprocal motion of an operating rod connected tosaid mechanism 14, the up and down movements of the sleeve 4 and the associated operation of the upper segmentsSand the lower segments 6 can be forcibly carried out. In the drawings, element 16 is a fixing plate for connecting the end of the operating rod 15 to the sleeve 4, and element 17 is a driving source for the forcibly reciprocating mechanism 14. Further, with respect to the second embodiment according to the present invention, it is of course possible to make such modifications of construction as mentioned in connection with the first embodiment, Furthermore as a forcibly reciprocating mechanism 14 to be provided in the casing pipe 1, it is also possible to adopt, in addition toan oil pressure piston, an air piston or any other mechanically driven reciprocating mechanism. The position 'where the forcibly reciprocating mechanism 14 is to be provided in the casing pipe 1 and the number of said mechanism to be provided should not be limited to what is shown in FIG. 3. That is, as shown in FIG. 10, the apparatus can be so constructed that a plurality of forcibly reciprocating mechanisms 14 are provided on the outer side of the upper portion of the casing pipe 1, an operating rod 15 of each of said mechanisms 14 being respectively provided along the outer wall of the casing pipe, and the lower end of said operating rod being fixed to the lower side of the sleeve 4. As shown in FIG. 1 1, it is also possible to provide the forcibly reciprocating mechanism in the outer side at the lower end portion of the casing pipe 1. The apparatus shown in the second embodiment of the present invention is the same as that in the first embodiment in principle. Also the features of use as well as function and effect thereof are equivalent to those of the first embodiment, but the characteristic feature of the second embodiment of the present invention consists of the following points: i.e., according to the apparatus in the first embodiment, in the case of the driving-in and pulling-out operations of the casing pipe 1 in the settlement of sand piles, the up and down movements of the sleeve 4 as well as the operation of the upper segments 5 and the lower segments 6 are automatically carried out but contrary to this, the apparatus in the second embodiment of the present invention is so constructed that the above-mentioned operation of the sleeve 4 as well as the upper segments 5 and the lower segments 6 are forcibly carried out by means of the operating rod 15 connected to the forcibly reciprocating mechanism 14 provided in the casing pipe 1.

The first embodiment of the present invention also can attain in general the expected result with a sufficiently favorable efficiency but if there is a great water content in the sand to fed into the casing pipe 1, the sand may choke the gap between the sleeve and the casing pipe or remain between the upper segments 5 and the lower segments 6.

In the apparatus of the second embodiment, the up and down movements of the sleeve 4 as well as the operation of the upper segments 5 and the lower segments 6 can be forcibly carried out by the mechanism 14, so that there is the advantage that an unimpeded operation of the apparatus can be effected.

It goes without saying that the sand pile forming apparatus according to the present invention can be employed for the purpose of forming, compacted piles consisting of all kinds of powdered or granular materials, such as gravel, crushed stone, and slag or the mixture of the same and sand, or mixtures of sand and caustic lime. Further, as. occasion demands, it is also possible to use the apparatus of the invention for forming loose sand piles as in the Sand Drain Method" or settling concrete piles in the ground.

Furthermore, in addition to the afore-mentioned modifications in the construction, various additional modifications are possible according to the present invention. For example, it should be noted that the present invention includes also the device, shown in FIGS. 8(a) and (b) in which the upper segments 5 and the lower segments 6 are covered with a durable cylindrical sheet or liner 18 having flexibility and elasticity thereby to prevent the movable portion from being choked up with sand, or the device shown in FIGS. 9(a) and (b), in which annular elastic block 19 such as sponge made of synthetic resin is inserted into the neck portion 7 formed by the upper segments 5 and the lower segments 6 thereby to prevent the movable portion from being choked up with sand.

What is claimed is:

1. Apparatus for forming sand piles and the like in the ground, said apparatus comprising a casing pipe which is generally vertically disposed and therefore has a lowermost end, a sleeve slidably disposed at' the lowermost end of said pipe and being adapted to project selectively below said end and to be in nesting relationship with said pipe, and collapsible means hinged to said pipe and to said sleeve to connect the same whereby when the pipe is partly withdrawn from the ground the sleeve can remain behind and project below said end, said collapsible means including hingedly connected sections adapted to form a relatively closed neck section when the sleeve and pipe are positioned in nesting relationship and which neck section opens up when the sleeve projects below said end upon partial withdrawal of the-pipe from the ground.

2. Apparatus as claimed in claim 1 comprising means for driving the pipe into and withdrawing the said pipe in steps out of the ground.

3. Apparatus as claimed in claim 1 comprising means for forcibly displacing said sleeve relative to said pipe.

4. Apparatus as claimed in claim 1 wherein said sleeve is within said pipe.

8. Apparatus as claimed in claim 1 wherein said collapsible means includes a group of upper segments hingedly connected to said pipe and a group of lower segments hingedly connected to said sleeve, the upper and lower segments being aligned and hingedly connected. 

1. Apparatus for forming sand piles and the like in the ground, said apparatus comprising a casing pipe which is generally vertically disposed and therefore has a lowermost end, a sleeve slidably disposed at the lowermost end of said pipe and being adapted to project selectively below said end and to be in nesting relationship with said pipe, and collapsible means hinged to said pipe and to said sleeve to connect the same whereby when the pipe is partly withdrawn from the ground the sleeve can remain behind and project below said end, said collapsible means including hingedly connected sections adapted to form a relatively closed neck section when the sleeve and pipe are positioned in nesting relationship and which neck section opens up when the sleeve projects below said end upon partial withdrawal of the pipe from the ground.
 1. Apparatus for forming sand piles and the like in the ground, said apparatus comprising a casing pipe which is generally vertically disposed and therefore has a lowermost end, a sleeve slidably disposed at the lowermost end of said pipe and being adapted to project selectively below said end and to be in nesting relationship with said pipe, and collapsible means hinged to said pipe and to said sleeve to connect the same whereby when the pipe is partly withdrawn from the ground the sleeve can remain behind and project below said end, said collapsible means including hingedly connected sections adapted to form a relatively closed neck section when the sleeve and pipe are positioned in nesting relationship and which neck section opens up when the sleeve projects below said end upon partial withdrawal of the pipe from the ground.
 2. Apparatus as claimed in claim 1 comprising means for driving the pipe into and withdrawing the said pipe in steps out of the ground.
 3. Apparatus as claimed in claim 1 comprising means for forcibly displacing said sleeve relative to said pipe.
 4. Apparatus as claimed in claim 1 wherein said sleeve is within said pipe.
 5. Apparatus as claimed in claim 1 wherein said sleeve encircles said pipe.
 6. Apparatus as claimed in claim 1 comprising a liner within said neck section.
 7. Apparatus as claimed in claim 1 comprising an annular member encircling said neck section. 